docs: def defaultDecoder(self, message, server):
          """Called to decode queries when no handler for that mode is found.
  
          @raises ProtocolError: This implementation always raises
              L{ProtocolError}.
          """
          mode = message.getArg(OPENID_NS, 'mode')
          fmt = "Unrecognized OpenID mode %r"
          raise ProtocolError(message, text=fmt % (mode,))